[PATCH v4] lib/math: Add int_sqrt test suite

[PATCH v4] lib/math: Add int_sqrt test suite

[Luis Felipe Hernandez]

Adds test suite for integer based square root function.

The test suite is designed to verify the correctness of the int_sqrt()
math library function.

Signed-off-by: Luis Felipe Hernandez <luis.hernandez093@gmail.com>
---
Changes in v2
  - Add new line at the end of int_sqrt_kunit.c
  - Add explicit header includes for MODULE_* macros, strscpy, and ULONG_MAX

Changes in v3
  - Remove unnecesary new line after Kconfig entry for INT_SQRT_KUNIT_TEST
  - Correct int_sqrt instances with int_sqrt() in commit message and kconfig
entry desc
  - Fix limits.h header include path

Changes in v4
  - Fix Kconfig entry: remove redundant word test
---
 lib/Kconfig.debug               | 15 ++++++++++
 lib/math/Makefile               |  1 +
 lib/math/tests/Makefile         |  1 +
 lib/math/tests/int_sqrt_kunit.c | 51 +++++++++++++++++++++++++++++++++
 4 files changed, 68 insertions(+)
 create mode 100644 lib/math/tests/int_sqrt_kunit.c

diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index f3d723705879..cc00c4ace855 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -3161,6 +3161,21 @@ config INT_POW_TEST
 
 	  If unsure, say N
 
+config INT_SQRT_KUNIT_TEST
+	tristate "Integer square root test test" if !KUNIT_ALL_TESTS
+	depends on KUNIT
+	default KUNIT_ALL_TESTS
+	help
+	  This option enables the KUnit test suite for the int_sqrt() function,
+	  which performs square root calculation. The test suite checks
+	  various scenarios, including edge cases, to ensure correctness.
+
+	  Enabling this option will include tests that check various scenarios
+	  and edge cases to ensure the accuracy and reliability of the square root
+	  function.
+
+	  If unsure, say N
+
 endif # RUNTIME_TESTING_MENU
 
 config ARCH_USE_MEMTEST
diff --git a/lib/math/Makefile b/lib/math/Makefile
index 3ef11305f8d2..25bcb968b369 100644
--- a/lib/math/Makefile
+++ b/lib/math/Makefile
@@ -9,3 +9,4 @@ obj-$(CONFIG_INT_POW_TEST)  += tests/int_pow_kunit.o
 obj-$(CONFIG_TEST_DIV64)	+= test_div64.o
 obj-$(CONFIG_TEST_MULDIV64)	+= test_mul_u64_u64_div_u64.o
 obj-$(CONFIG_RATIONAL_KUNIT_TEST) += rational-test.o
+obj-y  += tests/
diff --git a/lib/math/tests/Makefile b/lib/math/tests/Makefile
index 6a169123320a..e1a79f093b2d 100644
--- a/lib/math/tests/Makefile
+++ b/lib/math/tests/Makefile
@@ -1,3 +1,4 @@
 # SPDX-License-Identifier: GPL-2.0-only
 
 obj-$(CONFIG_INT_POW_TEST) += int_pow_kunit.o
+obj-$(CONFIG_INT_SQRT_KUNIT_TEST) += int_sqrt_kunit.o
diff --git a/lib/math/tests/int_sqrt_kunit.c b/lib/math/tests/int_sqrt_kunit.c
new file mode 100644
index 000000000000..3590142d2012
--- /dev/null
+++ b/lib/math/tests/int_sqrt_kunit.c
@@ -0,0 +1,51 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include <kunit/test.h>
+#include <linux/limits.h>
+#include <linux/math.h>
+#include <linux/module.h>
+#include <linux/string.h>
+
+struct test_case_params {
+	unsigned long x;
+	unsigned long expected_result;
+	const char *name;
+};
+
+static const struct test_case_params params[] = {
+	{ 0, 0, "edge-case: square root of 0" },
+	{ 4, 2, "perfect square: square root of 4" },
+	{ 81, 9, "perfect square: square root of 9" },
+	{ 2, 1, "non-perfect square: square root of 2" },
+	{ 5, 2, "non-perfect square: square root of 5"},
+	{ ULONG_MAX, 4294967295, "large input"},
+};
+
+static void get_desc(const struct test_case_params *tc, char *desc)
+{
+	strscpy(desc, tc->name, KUNIT_PARAM_DESC_SIZE);
+}
+
+KUNIT_ARRAY_PARAM(int_sqrt, params, get_desc);
+
+static void int_sqrt_test(struct kunit *test)
+{
+	const struct test_case_params *tc = (const struct test_case_params *)test->param_value;
+
+	KUNIT_EXPECT_EQ(test, tc->expected_result, int_sqrt(tc->x));
+}
+
+static struct kunit_case math_int_sqrt_test_cases[] = {
+	KUNIT_CASE_PARAM(int_sqrt_test, int_sqrt_gen_params),
+	{}
+};
+
+static struct kunit_suite int_sqrt_test_suite = {
+	.name = "math-int_sqrt",
+	.test_cases = math_int_sqrt_test_cases,
+};
+
+kunit_test_suites(&int_sqrt_test_suite);
+
+MODULE_DESCRIPTION("math.int_sqrt KUnit test suite");
+MODULE_LICENSE("GPL");
-- 
2.47.1

Re: [PATCH v4] lib/math: Add int_sqrt test suite

[Nicolas Pitre]

On Tue, 10 Dec 2024, Luis Felipe Hernandez wrote:

> Adds test suite for integer based square root function.
> 
> +struct test_case_params {
> +	unsigned long x;
> +	unsigned long expected_result;
> +	const char *name;
> +};
> +
> +static const struct test_case_params params[] = {
> +	{ 0, 0, "edge-case: square root of 0" },
> +	{ 4, 2, "perfect square: square root of 4" },
> +	{ 81, 9, "perfect square: square root of 9" },
> +	{ 2, 1, "non-perfect square: square root of 2" },
> +	{ 5, 2, "non-perfect square: square root of 5"},
> +	{ ULONG_MAX, 4294967295, "large input"},

This will fail on a 32-bit system where sizeof(long) == 32 and 
ULONG_MAX == 4294967295. (meaning the result would be 65535).


Nicolas

Re: [PATCH v4] lib/math: Add int_sqrt test suite

[Luis Felipe Hernandez]

On Tue, Dec 10, 2024 at 02:59:12PM -0500, Nicolas Pitre wrote:
> This will fail on a 32-bit system where sizeof(long) == 32 and 
> ULONG_MAX == 4294967295. (meaning the result would be 65535).

Thank you for taking the time to review my patch and for pointing out the issue with the ULONG_MAX test case. I failed to think about how a 32-bit system would treat ULONG_MAX == 4294967295.

To address this, I was thinking of updating the test case to use a large enough value that remains within the bounds of unsigned long for both 32-bit and 64-bit architectures instead. Specifically, 2147483648 (2^31), which has an integer square root of 46340. I believe this would ensure the test remains valid and portable across all supported architectures.

The updated test case would be as follows:
{ 2147483648, 46340, "large input"}

I'd appreciate any feedback on this proposed change and thanks again for your time Nicolas.

- Felipe

Re: [PATCH v4] lib/math: Add int_sqrt test suite

[Nicolas Pitre]

On Tue, 10 Dec 2024, Luis Felipe Hernandez wrote:

> On Tue, Dec 10, 2024 at 02:59:12PM -0500, Nicolas Pitre wrote:
> > This will fail on a 32-bit system where sizeof(long) == 32 and 
> > ULONG_MAX == 4294967295. (meaning the result would be 65535).
> 
> Thank you for taking the time to review my patch and for pointing out the issue with the ULONG_MAX test case. I failed to think about how a 32-bit system would treat ULONG_MAX == 4294967295.
> 
> To address this, I was thinking of updating the test case to use a large enough value that remains within the bounds of unsigned long for both 32-bit and 64-bit architectures instead. Specifically, 2147483648 (2^31), which has an integer square root of 46340. I believe this would ensure the test remains valid and portable across all supported architectures.
> 
> The updated test case would be as follows:
> { 2147483648, 46340, "large input"}

Sure.

And for such kind of test, more values to test is not a bad thing. So 
I'd suggest keeping { 4294967295, 65535 ] as well in the set as this 
represents a nice 
edge case.

It wouldn't hurt adding the entire set from 0 to 9 as well. Many 
different edge cases in that range.


Nicolas

Re: [PATCH v4] lib/math: Add int_sqrt test suite

[Luis Felipe Hernandez]

On Tue, Dec 10, 2024 at 10:58:02PM -0500, Nicolas Pitre wrote:

> And for such kind of test, more values to test is not a bad thing. So 
> I'd suggest keeping { 4294967295, 65535 ] as well in the set as this 
> represents a nice 
> edge case.
> 
> It wouldn't hurt adding the entire set from 0 to 9 as well. Many 
> different edge cases in that range.

I see, agreed, thank you for your suggestions. I'll go ahead and carry
out the following changes:
1. Replace the ULONG_MAX test case with the aforementioned { 2147483648,
46340, "large input"} case
2. Add the { 4294967295, 65535 } edge case
3. Add missing cases between 0 - 9
4. Add a couple more cases 

The updated test cases would be as follows:
{ 0, 0, "edge case: square root of 0" },
{ 1, 1, "perfect square: square root of 1" },
{ 2, 1, "non-perfect square: square root of 2" },
{ 3, 1, "non-perfect square: sqaure root of 3" },
{ 4, 2, "perfect square: square root of 4" },
{ 5, 2, "non-perfect square: square  root of 5" },
{ 6, 2, "non-perfect square: square root of 6" },
{ 7, 2, "non-perfect square: square root of 7" },
{ 8, 2, "non-perfect square: square root of 8" },
{ 9, 3, "perfect square: square root of 9" },
{ 16, 4, "perfect square: square root of 16" },
{ 81, 9, "perfect square: square root of 81" },
{ 256, 16, "perfect square: square root of 256" },
{ 2147483648, 46340, "large input: square root of 2147483648" },
{ 4294967295, 65535, "edge case: ULONG_MAX for 32-bit" },

I'll incorporate these changes and submit a new revision of this patch.
Please let me know if there's anything else you'd like me to address.

Thanks again for your guidance,

Felipe

Re: [PATCH v4] lib/math: Add int_sqrt test suite

[Nicolas Pitre]

On Tue, 10 Dec 2024, Luis Felipe Hernandez wrote:

> On Tue, Dec 10, 2024 at 10:58:02PM -0500, Nicolas Pitre wrote:
> 
> > And for such kind of test, more values to test is not a bad thing. So 
> > I'd suggest keeping { 4294967295, 65535 ] as well in the set as this 
> > represents a nice 
> > edge case.
> > 
> > It wouldn't hurt adding the entire set from 0 to 9 as well. Many 
> > different edge cases in that range.
> 
> I see, agreed, thank you for your suggestions. I'll go ahead and carry
> out the following changes:
> 1. Replace the ULONG_MAX test case with the aforementioned { 2147483648,
> 46340, "large input"} case
> 2. Add the { 4294967295, 65535 } edge case
> 3. Add missing cases between 0 - 9
> 4. Add a couple more cases 
> 
> The updated test cases would be as follows:
> { 0, 0, "edge case: square root of 0" },
> { 1, 1, "perfect square: square root of 1" },
> { 2, 1, "non-perfect square: square root of 2" },
> { 3, 1, "non-perfect square: sqaure root of 3" },
> { 4, 2, "perfect square: square root of 4" },
> { 5, 2, "non-perfect square: square  root of 5" },
> { 6, 2, "non-perfect square: square root of 6" },
> { 7, 2, "non-perfect square: square root of 7" },
> { 8, 2, "non-perfect square: square root of 8" },
> { 9, 3, "perfect square: square root of 9" },
> { 16, 4, "perfect square: square root of 16" },
> { 81, 9, "perfect square: square root of 81" },
> { 256, 16, "perfect square: square root of 256" },
> { 2147483648, 46340, "large input: square root of 2147483648" },
> { 4294967295, 65535, "edge case: ULONG_MAX for 32-bit" },
> 
> I'll incorporate these changes and submit a new revision of this patch.
> Please let me know if there's anything else you'd like me to address.

Looks fine to me.


Nicolas